Commands by dennisw (19)

If you cat the file, all the parts of the command line are bunched up. If you use tr to convert the nulls to spaces, you're still left without a newline unless you add another step. This command does everything for you.
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Dialog's gauge widget accepts progress updates on stdin. This version runs dialog once and updates it every second.
There's no need to use timeout which causes screen flicker since it restarts dialog for each update.

Pure Bash
This will print a row of characters the width of the screen without using any external executables. In some cases, COLUMNS may not be set. Here is an alternative that uses tput to generate a default if that's the case. And it still avoids using tr.
printf -v row "%${COLUMNS:-$(tput cols)}s"; echo ${row// /#}
The only disadvantage to either one is that they create a variable.
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A similar version for Bash that doesn't require cut and shortens the function in a few places. And it uses local variables. (similar to a version by eightmillion in a comment on the another version)
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Just one character longer than the sed version ('FNR==5' versus -n 5p). On my system, without using "exit" or "q", the awk version is over four times faster on a ~900K file using the following timing comparison:
testfile="testfile"; for cmd in "awk 'FNR==20'" "sed -n '20p'"; do echo; echo $cmd; eval "$cmd $testfile"; for i in {1..3}; do time for j in {1..100}; do eval "$cmd $testfile" >/dev/null; done; done; done
Adding "exit" or "q" made the difference between awk and sed negligible and produced a four-fold improvement over the awk timing without the "exit".
For long files, an exit can speed things up:
awk 'FNR==5{print;exit}' <file>

You can display, save and restore the value of $IFS using conventional Bash commands, but these functions, which you can add to your ~/.bashrc file make it really easy.
To display $IFS use the function ifs shown above. In the sample output, you can see that it displays the characters and their hexadecimal equivalent.
This function saves it in a variable called $saveIFS:
sifs () { saveIFS=$IFS; }
Use this function to restore it
rifs () { IFS=$saveIFS; }
Add this line in your ~/.bashrc file to save a readonly copy of $IFS:
declare -r roIFS=$IFS
Use this function to restore that one to $IFS
rrifs () { IFS=$roIFS; }Show Sample Output

I like the fact the Patola's version uses only ones and zeros, but I also like the sparse output of the other versions. This one combines both of those features and eliminates some unnecessary cruft.
You can vary the sparseness by changing "$(($RANDOM % 5))" to another number. The number in this term "$(($RANDOM % 4))" controls how frequently the numbers are output bold.

Bash 4 will let you do {00..19} to get leading zeros, but Bash 3 doesn't have that feature. This technique gets you partway there (the sequences need be such that the last digit ranges from zero to nine - you can't use this for something like Bash 4's {03..27}, for example). When this limitation is not a problem, you can avoid some complicated string manipulation for concatenating leading zeros.
You can add more digits like this: {0..1}{0..9}{0..9} (ranges from 0 to 99 with up to two leading zeros). To pad with additional zeros:
for i in 000{0..1}{0..9}; do echo $i; done
or
for i in {0..1}{0..9}; do echo "000$i"; done
This is useful for creating values to sort or for creating filenames with a fixed format. Note that this will also work:
touch {0..1}{0..9}Show Sample Output

If you should happen to find yourself needing some binary numbers, this is a quickie way of doing it. If you need more digits, just add more "{0..1}" sequences for each digit you need. You can assign them to an array, too, and access them by their decimal equivalent for a quickie binary to decimal conversion (for larger values it's probably better to use another method). Note: this works in bash, ksh and zsh. For zsh, though, you'll need to issue a setopt KSH_ARRAYS to make the array zero-based.
binary=({0..1}{0..1}{0..1}{0..1})echo ${binary[9]}Show Sample Output

This command displays a clock on your terminal which updates the time every second. Press Ctrl-C to exit.
A couple of variants:
A little bit bigger text:
watch -t -n1 "date +%T|figlet -f big"
You can try other figlet fonts, too.
Big sideways characters:
watch -n 1 -t '/usr/games/banner -w 30 $(date +%M:%S)'
This requires a particular version of banner and a 40-line terminal or you can adjust the width ("30" here).
Show Sample Output

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